package com.imooc.netty;

import io.netty.channel.Channel;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandlerAdapter;
import io.netty.handler.timeout.IdleState;
import io.netty.handler.timeout.IdleStateEvent;

/**
 * 用于检测channel的心跳handler
 * 继承ChannelInboundHandlerAdapter，从而不需要实现channelRead0方法
 *
 * @author 朝花不迟暮
 * @version 1.0
 * @date 2021/1/2 13:20
 */
public class HeartBeatHandler extends ChannelInboundHandlerAdapter
{
    @Override
    public void userEventTriggered(ChannelHandlerContext ctx, Object evt) throws Exception
    {
        // 判断evt是否是IdleStateEvent（用于触发用户事件，包含 读空闲/写空闲/读写空闲 ）
        if (evt instanceof IdleStateEvent)
        {
            IdleStateEvent event = (IdleStateEvent) evt;
            if (event.state() == IdleState.READER_IDLE)
            {
                System.out.println("进入读空闲...");
            } else if (event.state() == IdleState.WRITER_IDLE)
            {
                System.out.println("进入写空闲...");
            } else if (event.state() == IdleState.ALL_IDLE)
            {
                System.out.println("channel关闭前，clients的数量为：" + ChatHandler.clients.size());
                Channel channel = ctx.channel();
                // 关闭无用的channel，以防资源浪费
                channel.close();
                System.out.println("channel关闭后，clients的数量为：" + ChatHandler.clients.size());
            }
        }
    }
}
